SYDNEY, Australia (AFP) — A rare violet diamond, the largest of its kind ever found at Australia’s remote Argyle mine, will be the centerpiece of Rio Tinto’s annual pink diamonds showcase, the company said Tuesday. The rough gem, discovered in August 2015 at a mine where more than 90 percent of the world’s pink and red jewels are produced, originally weighed 9.17 carats and had etchings, pits and crevices. After weeks of assessment, the Argyle […]